74 lines
1.8 KiB
Rust
74 lines
1.8 KiB
Rust
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use serde::{Deserialize, Serialize};
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/// Get phase wrap from x to y.
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///
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/// Phases are modulo integer overflow.
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///
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/// Args:
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/// * `x`: Old phase sample
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/// * `y`: New phase sample
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///
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/// Returns:
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/// A tuple containg the (wrapped) phase difference and
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/// one times the direction of the wrap.
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pub fn get_wrap(x: i32, y: i32) -> (i32, i8) {
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let delta = y.wrapping_sub(x);
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let wrap = (delta >= 0) as i8 - (y >= x) as i8;
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(delta, wrap)
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}
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/// Phase unwrapper.
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#[derive(Copy, Clone, Default, Deserialize, Serialize)]
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pub struct Unwrapper {
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// last input
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x: i32,
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// last wraps
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v: i32,
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}
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impl Unwrapper {
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/// Unwrap a new sample from a phase sequence and update the
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/// unwrapper state.
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///
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/// Args:
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/// * `x`: New phase sample
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///
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/// Returns:
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/// A tuple containing the (wrapped) phase difference
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/// and the signed number of phase wraps corresponding to the new sample.
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pub fn update(&mut self, x: i32) -> (i32, i32) {
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let (dx, v) = get_wrap(self.x, x);
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self.x = x;
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self.v = self.v.wrapping_add(v as i32);
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(dx, self.v)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn mini() {
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for (x0, x1, v) in [
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(0i32, 0i32, 0i8),
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(1, 1, 0),
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(-1, -1, 0),
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(1, -1, 0),
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(-1, 1, 0),
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(0, 0x7fff_ffff, 0),
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(-1, 0x7fff_ffff, -1),
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(0, -0x8000_0000, 0),
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(1, -0x8000_0000, 1),
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(-0x6000_0000, 0x6000_0000, -1),
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(0x6000_0000, -0x6000_0000, 1),
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(0x6000_0000, -0x6000_0000, 1),
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(0x6000_0000, -0x6000_0000, 1),
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]
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.iter()
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{
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let (_dx, w) = get_wrap(*x0, *x1);
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assert_eq!(*v, w, " = get_wrap({:#x}, {:#x})", *x0, *x1);
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}
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}
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}
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